e2eaae1155
Sometimes nscd starts up before a /etc/resolv.conf file has been written, and apparently triggering a cache flush (reload) is not good enough to make it recover from that problem. To remedy the issue, we restart the service instead. See <https://github.com/NixOS/nixos/issues/34> for further details.
84 lines
2.7 KiB
Nix
84 lines
2.7 KiB
Nix
# /etc files related to networking, such as /etc/services.
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{config, pkgs, ...}:
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with pkgs.lib;
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let
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cfg = config.networking;
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options = {
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networking.extraHosts = pkgs.lib.mkOption {
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default = "";
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example = "192.168.0.1 lanlocalhost";
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description = ''
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Additional entries to be appended to <filename>/etc/hosts</filename>.
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'';
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};
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networking.dnsSingleRequest = pkgs.lib.mkOption {
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default = false;
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description = ''
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Recent versions of glibc will issue both ipv4 (A) and ipv6 (AAAA)
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address queries at the same time, from the same port. Sometimes upstream
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routers will systemically drop the ipv4 queries. The symptom of this problem is
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that 'getent hosts example.com' only returns ipv6 (or perhaps only ipv4) addresses. The
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workaround for this is to specify the option 'single-request' in
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/etc/resolve.conf. This option enables that.
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'';
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};
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};
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in
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{
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require = [options];
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environment.etc =
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{ # /etc/services: TCP/UDP port assignments.
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"services".source = pkgs.iana_etc + "/etc/services";
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# /etc/protocols: IP protocol numbers.
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"protocols".source = pkgs.iana_etc + "/etc/protocols";
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# /etc/rpc: RPC program numbers.
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"rpc".source = pkgs.glibc + "/etc/rpc";
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# /etc/hosts: Hostname-to-IP mappings.
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"hosts".text =
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''
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127.0.0.1 localhost
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${optionalString cfg.enableIPv6 ''
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::1 localhost
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''}
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${cfg.extraHosts}
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'';
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# /etc/resolvconf.conf: Configuration for openresolv.
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"resolvconf.conf".text =
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''
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# This is the default, but we must set it here to prevent
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# a collision with an apparently unrelated environment
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# variable with the same name exported by dhcpcd.
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interface_order='lo lo[0-9]*'
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'' + optionalString config.services.nscd.enable ''
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# Invalidate the nscd cache whenever resolv.conf is
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# regenerated.
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libc_restart='${pkgs.systemd}/bin/systemctl restart --no-block nscd.service'
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'' + optionalString cfg.dnsSingleRequest ''
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# only send one DNS request at a time
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resolv_conf_options='single-request'
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'' + optionalString config.services.bind.enable ''
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# This hosts runs a full-blown DNS resolver.
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name_servers='127.0.0.1'
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'';
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};
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# The ‘ip-up’ target is started when we have IP connectivity. So
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# services that depend on IP connectivity (like ntpd) should be
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# pulled in by this target.
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systemd.targets.ip-up.description = "Services Requiring IP Connectivity";
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}
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